如何进行流畅的 nhibernate 一对一映射? [英] How to do a fluent nhibernate one to one mapping?
问题描述
我该怎么做，我正在尝试进行一对一映射.
How do I do this I am trying to make a one to one mapping.
public class Setting
{
public virtual Guid StudentId { get; set; }
public virtual DateFilters TaskFilterOption { get; set; }
public virtual string TimeZoneId { get; set; }
public virtual string TimeZoneName { get; set; }
public virtual DateTime EndOfTerm { get; set; }
public virtual Student Student { get; set; }
}
//类图
public SettingMap()
{
/// Id(Reveal.Member<Setting>("StudentId")).GeneratedBy.Foreign("StudentId");
//Id(x => x.StudentId);
Map(x => x.TaskFilterOption).Default(DateFilters.All.ToString()).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.TimeZoneId).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.TimeZoneName).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.EndOfTerm).Default("5/21/2011").Not.Nullable();
HasOne(x => x.Student);
}
//学生图
public class StudentMap : ClassMap<Student>
{
public StudentMap()
{
Id(x => x.StudentId);
HasOne(x => x.Setting).Cascade.All();
}
}
public class Student
{
public virtual Guid StudentId { get; private set; }
public virtual Setting Setting { get; set; }
}
现在每次我尝试创建设置对象并将其保存到数据库时都会崩溃.
Now every time I try to create a settings object and save it to the database it crashes.
Setting setting = new Setting
{
TimeZoneId = viewModel.SelectedTimeZone,
TimeZoneName = info.DisplayName,
EndOfTerm = DateTime.UtcNow.AddDays(-1),
Student = student
};
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Settings_Students". The conflict occurred in database "Database", table "dbo.Students", column 'StudentId'.
The statement has been terminated.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Data.SqlClient.SqlException: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Settings_Students". The conflict occurred in database "Database", table "dbo.Students", column 'StudentId'.
The statement has been terminated.
我错过了什么?
编辑
public class StudentMap : ClassMap<Student>
{
public StudentMap()
{
Id(x => x.StudentId).GeneratedBy.Guid();
HasOne(x => x.Setting).PropertyRef("Student").Cascade.All();
}
}
public class SettingMap : ClassMap<Setting>
{
public SettingMap()
{
Id(x => x.StudentId).GeneratedBy.Guid();
Map(x => x.TaskFilterOption).Default(DateFilters.All.ToString()).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.TimeZoneId).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.TimeZoneName).NvarcharWithMaxSize().Not.Nullable();
Map(x => x.EndOfTerm).Default("5/21/2011").Not.Nullable();
References(x => x.Student).Unique();
}
}
// try 1
Setting setting = new Setting
{
TimeZoneId = viewModel.SelectedTimeZone,
TimeZoneName = info.DisplayName,
EndOfTerm = DateTime.UtcNow.AddDays(-1),
Student = student
};
studentRepo.SaveSettings(setting);
studentRepo.Commit();
// try 2
Setting setting = new Setting
{
TimeZoneId = viewModel.SelectedTimeZone,
TimeZoneName = info.DisplayName,
EndOfTerm = DateTime.UtcNow.AddDays(-1),
Student = student
};
student.Setting = setting
studentRepo.CreateStudent(student);
studentRepo.Commit();
我在两种情况下都收到这些错误
I get these error for both ways
Invalid index 5 for this SqlParameterCollection with Count=5. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.IndexOutOfRangeException: Invalid index 5 for this SqlParameterCollection with Count=5.
Source Error:
Line 76: using (ITransaction transaction = session.BeginTransaction()) Line 77: { Line 78: transaction.Commit(); Line 79: } Line 80: }
推荐答案
如何在 NH 中映射双向一对一关联有两种基本方法.假设类如下所示:
There are two basic ways how to map bidirectional one-to-one association in NH. Let's say the classes look like this:
public class Setting
{
public virtual Guid Id { get; set; }
public virtual Student Student { get; set; }
}
public class Student
{
public virtual Guid Id { get; set; }
public virtual Setting Setting { get; set; }
}
设置类是关联中的大师(聚合根").这很不寻常，但它取决于问题域...
Setting class is a master in the association ("aggregate root"). It is quite unusual but it depends on problem domain...
主键关联
public SettingMap()
{
Id(x => x.Id).GeneratedBy.Guid();
HasOne(x => x.Student).Cascade.All();
}
public StudentMap()
{
Id(x => x.Id).GeneratedBy.Foreign("Setting");
HasOne(x => x.Setting).Constrained();
}
并且应该存储一个新的设置实例:
and a new setting instance should be stored:
var setting = new Setting();
setting.Student = new Student();
setting.Student.Name = "student1";
setting.Student.Setting = setting;
setting.Name = "setting1";
session.Save(setting);
外键关联
public SettingMap()
{
Id(x => x.Id).GeneratedBy.Guid();
References(x => x.Student).Unique().Cascade.All();
}
public StudentMap()
{
Id(x => x.Id).GeneratedBy.Guid();
HasOne(x => x.Setting).Cascade.All().PropertyRef("Student");
}
主键关联接近您的解决方案.仅当您绝对确定关联将始终是一对一的时，才应使用主键关联.请注意，NH 中的一对一不支持 AllDeleteOrphan 级联.
Primary key association is close to your solution. Primary key association should be used only when you are absolutely sure that the association will be always one-to-one. Note that AllDeleteOrphan cascade is not supported for one-to-one in NH.
有关更多详细信息，请参阅:
For more details see:
http://fabiomaulo.blogspot.com/2010/03/conform-mapping-one-to-one.html
http://ayende.com/blog/3960/nhibernate-一对一映射
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